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		<h1 id="0041-dialogs-vii---the-colorchooserdialog">0041: Dialogs VII - The ColorChooserDialog</h1>

<p>We’ve actually seen today’s topic widget before, but it was part-n-parcel of the <code class="language-plaintext highlighter-rouge">ColorButton</code>, so we didn’t really look at it because it was a behind-the-scenes kind of dialog. Today, though, we’re gonna roll up our sleeves and see how this sucker works.</p>

<div class="screenshot-frame">
	<div class="frame-header">
		Results of this example:
	</div>
	<div class="frame-screenshot">
		<figure>
			<img id="img0" src="../images/screenshots/013_dialogs/dialog_07.png" alt="Current example output" />		<!-- img# -->
			
			<!-- Modal for screenshot -->
			<div id="modal0" class="modal">																	<!-- modal# -->
				<span class="close0">&times;</span>															<!-- close# -->
				<img class="modal-content" id="img00" />															<!-- img## -->
				<div id="caption"></div>
			</div>
			
			<script>
			// Get the modal
			var modal = document.getElementById("modal0");														// modal#
			
			// Get the image and insert it inside the modal - use its "alt" text as a caption
			var img = document.getElementById("img0");															// img#
			var modalImg = document.getElementById("img00");													// img##
			var captionText = document.getElementById("caption");

			img.onclick = function()
			{
			  modal.style.display = "block";
			  modalImg.src = this.src;
			  captionText.innerHTML = this.alt;
			}
			
			// Get the <span> element that closes the modal
			var span = document.getElementsByClassName("close0")[0];											// close#
			
			// When the user clicks on <span> (x), close the modal
			span.onclick = function()
			{ 
				modal.style.display = "none";
			}
			</script>
			<figcaption>
			Current example output
			</figcaption>
		</figure>
	</div>

	<div class="frame-terminal">
		<figure class="right">
			<img id="img1" src="../images/screenshots/013_dialogs/dialog_07_term.png" alt="Current example terminal output" />		<!-- img#, filename -->

			<!-- Modal for terminal shot -->
			<div id="modal1" class="modal">																				<!-- modal# -->
				<span class="close1">&times;</span>																		<!-- close# -->
				<img class="modal-content" id="img11" />																		<!-- img## -->
				<div id="caption"></div>
			</div>
			
			<script>
			// Get the modal
			var modal = document.getElementById("modal1");																	// modal#
			
			// Get the image and insert it inside the modal - use its "alt" text as a caption
			var img = document.getElementById("img1");																		// img#
			var modalImg = document.getElementById("img11");																// img##
			var captionText = document.getElementById("caption");

			img.onclick = function()
			{
			  modal.style.display = "block";
			  modalImg.src = this.src;
			  captionText.innerHTML = this.alt;
			}
			
			// Get the <span> element that closes the modal
			var span = document.getElementsByClassName("close1")[0];														// close#
			
			// When the user clicks on <span> (x), close the modal
			span.onclick = function()
			{ 
				modal.style.display = "none";
			}
			</script>

			<figcaption>
				Current example terminal output (click for enlarged view)
			</figcaption>
		</figure>
	</div>

	<div class="frame-footer">																								<!-- ------------- filename (below) --------- -->
		The code file for this example is available <a href="https://github.com/rontarrant/gtkd_demos/blob/master/013_dialogs/dialog_07_ColorChooserDialog.d" target="_blank">here</a>.
	</div>
</div>

<p>In this example, I’ve defined a <code class="language-plaintext highlighter-rouge">ColorChooserButton</code> based on a plain vanilla <code class="language-plaintext highlighter-rouge">Button</code> which, in effect, makes this newly-derived <code class="language-plaintext highlighter-rouge">ColorChooserButton</code> equivalent to the <code class="language-plaintext highlighter-rouge">ColorButton</code> we saw in <a href="./0023-radio-and-color-buttons.html">Blog Post #23</a> (and <a href="https://github.com/rontarrant/gtkd_demos/blob/master/010_more_buttons/button_010_02_colorbutton.d">the code file for that can be found here</a>, if you care to have another look at it).</p>

<h2 id="the-button-that-opens-the-dialog">The Button that Opens the Dialog</h2>

<p>However, there are differences, so let’s look at what we’ve got here in this new button:</p>

<div class="language-d highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="k">class</span> <span class="n">ColorChooserButton</span> <span class="p">:</span> <span class="n">Button</span>
<span class="p">{</span>
	<span class="k">private</span><span class="p">:</span>
	<span class="nb">string</span> <span class="n">labelText</span> <span class="p">=</span> <span class="s">"Ask for a Color"</span><span class="p">;</span>
	
	<span class="n">MyColorChooserDialog</span> <span class="n">colorChooserDialog</span><span class="p">;</span>
	<span class="n">Window</span> <span class="n">_parentWindow</span><span class="p">;</span>
	
	<span class="k">public</span><span class="p">:</span>
	<span class="k">this</span><span class="p">(</span><span class="n">Window</span> <span class="n">parentWindow</span><span class="p">)</span>
	<span class="p">{</span>
		<span class="k">super</span><span class="p">(</span><span class="n">labelText</span><span class="p">);</span>
		<span class="n">addOnClicked</span><span class="p">(&amp;</span><span class="n">doSomething</span><span class="p">);</span>
		<span class="n">_parentWindow</span> <span class="p">=</span> <span class="n">parentWindow</span><span class="p">;</span>
		
	<span class="p">}</span> <span class="c1">// this()</span>
	
	
	<span class="kt">void</span> <span class="n">doSomething</span><span class="p">(</span><span class="n">Button</span> <span class="n">b</span><span class="p">)</span>
	<span class="p">{</span>
		<span class="n">colorChooserDialog</span> <span class="p">=</span> <span class="k">new</span> <span class="n">MyColorChooserDialog</span><span class="p">(</span><span class="n">_parentWindow</span><span class="p">);</span>
		
	<span class="p">}</span> <span class="c1">// doSomething()</span>

<span class="p">}</span> <span class="c1">// class: ColorChooserButton</span>
</code></pre></div></div>

<p>Here—because we’re driving the boat, as it were—we have to declare our own dialog which we didn’t have to do with the <code class="language-plaintext highlighter-rouge">ColorButton</code>. And naturally, we’ve got to hook up a signal too, so that clicking on the button opens the dialog. Then there’s the whole modal rigmarole to deal with, so we have to pass a pointer to the parent window along to our dialog object…</p>

<h2 id="and-now-the-dialog">And Now, the Dialog</h2>

<p>For which the code looketh thus like:</p>

<div class="language-d highlighter-rouge"><div class="highlight"><pre class="highlight"><code><span class="k">class</span> <span class="n">MyColorChooserDialog</span> <span class="p">:</span> <span class="n">ColorChooserDialog</span>
<span class="p">{</span>
	<span class="k">private</span><span class="p">:</span>
	<span class="nb">string</span> <span class="n">title</span> <span class="p">=</span> <span class="s">"I am the Chooser"</span><span class="p">;</span>
	<span class="n">DialogFlags</span> <span class="n">flags</span> <span class="p">=</span> <span class="n">GtkDialogFlags</span><span class="p">.</span><span class="n">MODAL</span><span class="p">;</span>
	<span class="n">RGBA</span> <span class="n">selectedColor</span><span class="p">;</span>

	<span class="k">public</span><span class="p">:</span>
	<span class="k">this</span><span class="p">(</span><span class="n">Window</span> <span class="n">_parentWindow</span><span class="p">)</span>
	<span class="p">{</span>
		<span class="k">super</span><span class="p">(</span><span class="n">title</span><span class="p">,</span> <span class="n">_parentWindow</span><span class="p">);</span>
		<span class="n">addOnResponse</span><span class="p">(&amp;</span><span class="n">doSomething</span><span class="p">);</span>
		<span class="n">run</span><span class="p">();</span> <span class="c1">// no response ID because this dialog ignores it</span>
		<span class="n">destroy</span><span class="p">();</span>
		
	<span class="p">}</span> <span class="c1">// this()</span>

	<span class="k">protected</span><span class="p">:</span>
	<span class="kt">void</span> <span class="n">doSomething</span><span class="p">(</span><span class="kt">int</span> <span class="n">response</span><span class="p">,</span> <span class="n">Dialog</span> <span class="n">d</span><span class="p">)</span>
	<span class="p">{</span>
		<span class="n">getRgba</span><span class="p">(</span><span class="n">selectedColor</span><span class="p">);</span>
		<span class="n">writeln</span><span class="p">(</span><span class="s">"New color selection: "</span><span class="p">,</span> <span class="n">selectedColor</span><span class="p">);</span>
		
	<span class="p">}</span> <span class="c1">// doSomething()</span>
	
<span class="p">}</span> <span class="c1">// class MyColorChooserDialog</span>
</code></pre></div></div>

<p>As you can see, this is a derivation of the <code class="language-plaintext highlighter-rouge">ColorChooserDialog</code>, mostly because I wanted to illustrate a couple of points:</p>

<ul>
  <li>first, I’ve used the <code class="language-plaintext highlighter-rouge">addOnResponse()</code> function to hook up the signal, same as with the <code class="language-plaintext highlighter-rouge">MessageDialog</code>, but different from the <code class="language-plaintext highlighter-rouge">FileChooserDialog</code> (for which we used: <code class="language-plaintext highlighter-rouge">addOnActivate()</code>),</li>
  <li>second, the <em>response ID</em> for the dialog is ignored.</li>
</ul>

<p>Yup, this is one dialog that doesn’t care which button you click to close it. And why? Because it’s got a default color already picked out for you: white (255, 255, 255) so there’s always a color available when you call <code class="language-plaintext highlighter-rouge">getRbga()</code>, even if you don’t explicitly pick a new one.</p>

<p>So, what if you pick a new color, let’s say <code class="language-plaintext highlighter-rouge">rgb(245, 121, 0)</code>, a nice middle-of-the-road orange, but then next time you open the dialog, you hit the cancel button. Does the orange remain as the default pick?</p>

<p>Nope. It goes back to white.</p>

<h2 id="which-is-best">Which is Best?</h2>

<p>You may wonder which of these methods of picking a color is best, the <code class="language-plaintext highlighter-rouge">ColorChooserDialog</code> or the <code class="language-plaintext highlighter-rouge">ColorButton</code>… It depends on the circumstances you find yourself in while designing an application:</p>

<ul>
  <li>if you plan to have access through a menu, you’ll want to use the dialog,</li>
  <li>for access from menu, toolbar and button, again: dialog, but</li>
  <li>for accessing the dialog only from a button, the <code class="language-plaintext highlighter-rouge">ColorButton</code> will do fine.</li>
</ul>

<p>Another thing to take into consideration is whether or not you want that default white color haunting your application. You could deal with it by using an <code class="language-plaintext highlighter-rouge">ObservedColor</code> object like we did in <a href="https://github.com/rontarrant/gtkd_demos/blob/master/010_more_buttons/button_010_02_colorbutton.d">the ColorButton example</a>. And even if you decide to go with the <code class="language-plaintext highlighter-rouge">ColorChooserDialog</code>, an <code class="language-plaintext highlighter-rouge">ObservedColor</code> can still be nudged in the right direction so as to serve your purposes.</p>

<p>And that’s the <code class="language-plaintext highlighter-rouge">ColorChooserDialog</code>.</p>

<p>Take care and see you next time.</p>

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